It is known in the technical sector of packaging products in liquid form, powder form and the like that there exists the need to produce thermoplastic containers suitable for this purpose.
It is also known that said containers are formed in suitable machines comprising a mould into which a predefined quantity of material is injected and then subjected to a first mechanical moulding deformation in order to obtain a so-called “preform” which, in turn, is then subjected to blowing—which may be preceded by a heat conditioning treatment—in order to arrive at the final form of the container.
It is also known that said cycle may be divided into two different steps performed on different machines (called single-stage machines) for respectively producing the “preforms” and blow-moulding said preforms in order to obtain the finished container.
Vice versa, the two production steps may be combined in a single machine called a dual-stage machine. In both cases the machines comprise an injection mould formed by two half-parts which may close and open to allow injection into the mould of the material in the softened state and the subsequent extraction of the preforms, already cooled; subsequent forming of the container is performed in a second blowing mould downstream of the injection mould.